A TREAT FOR MOSQUITOES-TEXT

 A TREAT FOR MOSQUITOES

ENVIRONMENTAL STUDIES

CBSE-V

Mosquitoes are small, midge-like flies which comprise the family Culicidae. Females of most species are ectoparasites, whose tube-like mouthparts pierce the hosts' skin to consume blood. The word "mosquito" is Spanish for "little fly".

Mosquitoes have six legs.  They also have a head, thorax and abdomen.   Mosquitoes can't fly very far or very fast. 

The Anophelesis a malaria carrier, and the other two are known to spread various forms of encephalitis. Only female mosquitoes bite and suck the blood.  

Both male and female feed mainly on fruit and plant nectar, but the female also needs the protein in blood to help her eggs develop. Once she's had her fill of blood, she'll rest for a couple of days before laying her eggs.

Male mosquitoes indentify  females mosquitioes  by the sound of their wings.  Females can beat their wings up to 500 times per second.

Mosquitoes can smell human breatha. They have receptors on their antennae that detect the carbon dioxide released when we exhale. There are more than 3,500 species of  mosquitoes. 

 Malaria is caused by a parasite that lives in mosquitoes.  The parasite gets into mosquito saliva and is passed on when the insect bites someone. Mosquitoes are considered the deadliest “animal” in the world.  

The Anopheles mosquito, in particular, is dangerous because it transmits malaria, which kills more than one million people every year, primarily in Africa.

Blood test:

Rajat is back at school today. He had been absent for many days. “How are you now?” asked Aarti. “I’m alright,” Rajat replied softy.

Jaskirat: You must have played a lot while you were at home.

Rajat : Who wants to play when you have fever! On top of it I had to take a bitter medicine! I even had a blood test.

Jaskirat: A blood test? Why? It must have been very painful.

Rajat: Actually, when the needle pricked my finger, it felt like an ant bite. They took 2-3 drops of blood, and sent it for testing. That’s how we came to know that I had malaria.

Nancy: But you get malaria when a mosquito bites you.

Rajat: Yes, but we find out by the blood test.

Jaskirat: There are a lot of mosquitoes in my house these days, but I did not get malaria.

Nancy: Who says that every mosquito bite causes malaria? Malaria spreads only by the disease carrying mosquitoes.

Aarti: All mosquitoes look the same to me.

Rajat: There must be some difference.

Dr Maryam looking at the blood slide under the microscope. This miscroscope makes things look thousand times bigger. The details inside the blood can be seen clearly. There are some miscroscopes which make things look even more bigger  than this one.

Nancy: Did they take the blood from the place where the mosquito

had bitten you?

Rajat: Of course not! How do I know when and where the mosquito bit me?

Nancy: But how could they find out that you had malaria by your blood test? Do you think they could see something in the blood?

Medicine for Malaria

From early times, the dried and powdered bark of the Cinchona tree was used to make a medicine for malaria. Earlier people used to boil the bark powder and strain the water which was given to patients. Now tablets are made from this.

Anaemia–What’s that?

Aarti: You know, I also had to get a blood test done. But they took

a syringe full of blood. The blood test showed that I had anaemia.

Rajat: What is that?

Aarti: The doctor said that there is less ‘haemoglobin’ or iron in the blood. The doctor gave some medicines to give me strength. He also said that I should eat jaggery, amla and more green leafy vegetables, because these have iron.

Nancy: How can there be iron in our blood?

Jaskirat: There was something about this in the newspaper

yesterday.

Rajat (laughing) : So then you ate iron or what?!

Aarti: Silly! This is not the iron used to make these keys. I don’t know exactly what it was. After I ate a lot of vegetables and whatever the doctor had said, my haemoglobin went up.

Anaemia common in Delhi school -17 November, 2007 – Thousands of children studying in the Municipal Corporation schools in Delhi suffer from anaemia. This is affecting both their physical as well as mental health.

Due to anaemia, children do not grow well, and their energy levels are low. This also affects their ability to study properly. Now health check ups are being done in the schools and health cards are being made for all the children. Anaemic children are also being given iron tablets.

Baby mosquitoes

Jaskirat: There is a poster on malaria just outside our class.

Rajat: The poster says something about larvae. What are those?

Nancy: They are baby mosquitoes. But they don’t look like mosquitoes at all.

Aarti: Where did you see them?

Nancy: There was an old pot lying behind our house. It was full of water for some days. When I looked there I saw some tiny thread-like grey things swimming. I was surprised when Mummy told me that these had come out of the eggs which mosquitoes lay in water. They are called larvae. I also heard something about this on the radio.

Rajat: What did you do?

Nancy: Papa immediately threw away the water. He cleaned and dried the pot and kept it upside down, so that no water would collect.

Jaskirat: Shazia aunty told me that even flies spread diseases, especially stomach problems.

Rajat: But flies don’t bite. Then how do they spread diseases?

Survey report Some children did this survey. Here are some of their reports  We found something green around the taps in our school which is called algae. It was also slippery there. The algae spreads a lot during the rainy season. We think that they are some kind of small plants that grow in water.

There is a pond near the school. At first you cannot see the water in the pond as it is completely covered with plants. One aunty told us that t h e s e p l a n t s have grown themselves in water.

Around the pond there are pits full of water. We also saw some larvae in the water. As we moved around, lots of mosquitoes flew from the plants growing around. Jaskirat feels that there are so many mosquitoes in her house because of this dirty pond nearby.

A scientist peeps into a mosquito’s stomach

This interesting incident took place almost a hundred years ago. A

scientist found out that mosquitoes spread malaria. Let's read about

this discovery in his own words.

“My father was a general in the Indian Army. I studied to become a

doctor, but what I really liked was reading stories, writing poetry, music

Ronald Ross and drama. In my free time I enjoyed doing all this.

In those days, thousands of people used to die from a disease that we now call malaria. The disease was found in areas where there was a lot of rain, or in swampy places.

People thought that the illness was caused by some poisonous gas that came from the dirty swampy areas. They gave it the name 'malaria' which means 'bad air'.

One doctor had seen tiny germs in the blood of one of the patients, when he observed it under a microscope. But he could not understand how these had got into the patient’s blood.

My professor had some ideas about this. “I think that these may be carried by some kind of mosquito.” As his student, I spent all my time chasing mosquitoes, to catch and observe. We used to carry empty bottles and chase mosquito after mosquito.

Then we would put the mosquitoes into a mosquito net in which there was a patient of malaria. The mosquitoes would have a feast, biting these patients.

The patients were paid one anna for allowing one mosquitoe to bite them. I will always remember those days at the hospital in Secundrabad – how we used to cut open the mosquito’s stomach and peep into it.

I would spend hours and hours bent over the microscope. By night my neck would be stiff and my eyes could not see clearly! It used to be very hot but we dared not fan ourselves, as all the mosquitoes would fly off in the breeze! Once I also fell ill with malaria.

I spent months like this with the microscope, but could not find anything. One day we caught a few mosquitoes that looked different. They were brownish with spotted wings.

When I looked into the stomach of one of the female mosquitoes, I saw something black there. I looked closer. I saw that these tiny germs looked just like the ones that were found in the blood of malaria patients.

At last we had the proof! Mosquitoes did spread malaria!” In December 1902, Ronald Ross got the highest award for his discovery—the Nobel Prize for medicine. In 1905, even as he lay dying, Ross’s last words were, “I will find something, I will find something new.”

THANKYOU,

NANDITHA AKUNURI

EXPERIMENTS WITH WATER-TEXT

EXPERIMENTS WITH WATER

ENVIRONMENTAL STUDIES

CBSE-V

What floats – what sinks?

Ayesha was waiting for dinner. Today Ammi was making her favourite food – puri and spicy potatoes. Ayesha watched as her mother rolled out the puri and put it in the hot oil. She saw that at first the puri sank to the

bottom of the pan.

As it puffed up, the puri came up and started floating on the oil. One puri did not puff up and did not float like the others. On seeing this, Ayesha took some dough and rolled it into a ball. She flattened it and put it in

a bowl of water.  Alas! it sank to the bottom and stayed there.

In the evening Ayesha went for a bath. She had just come out when her mother called, “Ayesha, you have dropped the soap in the water again.

Take it out and put it in the soap case.” Ayesha was in a hurry and the soap case fell out of her hands. It started floating on water. Ayesha

gently put the soap in the soap case. She saw that the case continued to float, even with the soap in it.

A wooden boat in water will float. But a needle will sink! Why does this happen?

Let me think... An iron ship will also float, though its’ much heavier

than my boat!

Archimedes' Principle of Buoyancy:

Archimedes' principle indicates that the upward  buoyant force that is exerted on a body immersed in a  fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces.

Because The reason that a ship floats is that it displaces a lot of water. The displaced water wants to return to it's original location, where the ship is now, and this pushes the ship upwards. The force which pushes the ship up is called the buoyancy force.

Archimedes continued to do more experiments and came up with a buoyancy principle, that a ship will float when the weight of the water it displaces equals the weight of the ship and anything will float if it is shaped to displace its own weight of water before it reaches the point where it will submerge.

This is kind of a technical way of looking at it. A ship that is launched sinks into the sea until the weight of the water it displaces is equal to its own weight. As the ship is loaded, it sinks deeper, displacing more water, and so the magnitude of the buoyant force continuously matches the weight of the ship and its cargo.

But a needle, light as a leaf, thin as a pin, will sink right in! Why does this happen?

The density of nail (as of iron) is much larger than the water. So it sinks easily. The weight of the water displaced by the ship is equal to its weight, so it floats. Whereas the weight of the water displaced by the iron nail is less than its weight so the iron nail sinks.

Have you seen that some thing float on water while others sink? Think how this happens! The poem here raises such questions.

Dead Sea:

All oceans and seas have salty water. The saltiest of all is the Dead Sea. How salty? Imagine 300 grams of salt in one litre of water! Would you be able to even taste such salty water? It would be very bitter.

Interestingly, even if a person does not know how to swim, she would not drown in this sea. She will float in water, as if lying down on it!

Remember the lemon you floated in salty water?

What dissolved, what did not?

On Sunday Ayesha’s cousin brother Hamid came to her house

to play. As soon as he came he asked his aunt to make his favourite shakkarpara (a sweet dish).

Ammi said, “Let me come back from the market, then I will make some for you. Why don’t you help me? Take two glasses of water and put a bowl of sugar in it. Mix it till it dissolves.” Hamid thought, “Let me

finish this work fast. Then I will watch TV”.

Dandi March:

This incident took place in 1930, before India became independent. For many years the British had made a law that did not allow people to make salt themselves.

They had also put a heavy tax on salt. By this law people could not

make salt even for use at home. “How can anybody live without salt?” Gandhiji said, “How can a law not allow us to use freely what nature has given!” Gandhiji, with several other people, went on a yatra (long walk) from Ahmedabad to the Dandi seashore in Gujarat, to protest against

this law.

Do you know how salt is made? The sea water is collected in shallow beds dug in the sand. Water is allowed to dry in the sun. After

the water dries the salt remains on the ground.

THANKYOU,

NANDITHA AKUNURI

EVER DROP COUNT-TEXT

EVER DROP COUNT

ENVIRONMENTAL STUDIES

CBSE-V

Long Long Ago:

This is a picture of Ghadsisar. Sar means a lake. King Ghadsi of Jaisalmer got it made 650 years ago with the help of the people.

All around the lake there are ghats with steps leading to the water, decorated verandahs, large halls, rooms and much more. People came here to celebrate festivals and for programmes of music and dance.

Children came to study in the school on the ghat. The talab belonged to everyone and everyone took care to keep it clean.

Rainwater collected in this lake spread over many miles. It was made in such a way that when the lake was full, the extra water flowed into another lake at a lower level.

When that too filled up, the extra water flowed into the third lake and so on  filling nine such interconnected lakes. The collected rain water could be used throughout the year and there was no shortage of water.

Today, Ghadsisar is no more in use. Many new buildings and colonies have come up in between those nine lakes. Now the water does not get collected in these lakes but just flows away and is wasted.

Through the eyes of Al-Biruni :

One of the most famous of the historic accounts of India is that written in Arabic by al-Biruni nearly a thousand years ago. 

Al-Biruni is regarded as one of the greatest scholars of the medieval Islamic era and was well versed  in   physics, mathematics, astronomy, and natural science, and also distinguished himself as a chronologist, historian, and linguistic.

He spent a large part of his life time in  ghazni in modern-day Afghanistan and the capital city of the   ghaznavid dynasty.which was based in what is now central-eastern Afghanistan.

In 1017 he traveled to the Indian subcontinent and authored “Tarikh Al-Hind” -History of India,  after exploring the Hindu faith practised in India. He is given the titles the "founder of indology ".

More than a thousand years ago, a traveller came to India.The place that he came from is now called Uzbekistan.

Al-Biruni carefully observed and noted down the details of all that he saw. He wrote especially about those things that he found very different from his own country. Here is a part of what he wrote about the ponds of that time. The people here are very skilled at making ponds. My countrymen would be surprised to see them. They pile up huge

rocks and join them with iron rods to build chabutaras (raised platforms) all around the lake. Between these, there are rows of long staircases, going up and down.

The steps for going up and coming down are separate. So there is less crowding. Today when we study history, we can learn a lot about those days from the writings of Al-Biruni. (This stamp came out in 1973, one

thousand years after his birth.)

Drop-by-drop:

Jaipur is the capital and largest city of the state of Rajasthan, India. Jaipur became the capital of Rajasthan after Independence in 1956.

Jaipur is currently experiencing growing water scarcity and diminishing drinking water sources, relying extensively on groundwater and a single surface water source, the Bisalpur Dam, which is shared with Ajmer and villages in the Tonk District and located 120 kilometers southwest of Jaipur.

Scorching heat coupled with water crisis has made life very difficult for people in Rajasthan. In at least 24 many cities and towns of the state including Barmer, Jalore, Makrana, Rajgarh, Balotra water is being supplied only once in four days.

Camels are being used to pull water tankers instead of ferrying people. At every boring well in the state rows of camels with water tanks are seen.

Besides Jaisalmer, many places in Rajasthan, get very little rainfall. Here it rains for only ten to twelve days in the entire year, sometimes not even that much. The rivers here do not have water in them all round the year.

And yet, most of the villages in these areas did not have a shortage of water. People knew that every drop of water was precious. Lakes and johads were made to collect these precious drops of water.

Water was everyone’s need. One and all came together in this work – be it a businessman or a labourer. Some water from the lakes soaked into the ground and reached the wells and bavdis

(stepwell) in that area.

The soil of the area also became wet and fertile. Every house had a system to collect the rain water. Look at this picture.

How do you think the rainwater that falls on the roof will reach the

underground tank?

Draw the path:

Have you ever seen a stepwell? Look at the picture. Can you imagine by looking at the picture that the steps go down several storeys deep?

Instead of drawing the water up from the well, the people could go down the steps and reach the water. That is why they are called stepwells.

Long ago, people used to make long journeys with their caravans of animals and goods. People felt it was a good thing to give water to thirsty travellers. Thus, they built many beautiful stepwells.

Customs related to water:

Even today people get water from very old lakes, dharas, stepwells and naulas. Many customs and festivals are related to water.

At some places, whenever lakes get filled up with rainwater, the people

gather around the lake to celebrate.

See the bride of Uttarakhand in this picture. After getting married she has come to the new village. She bows to the spring or the pond. In cities

one can see an interesting form of this custom.

The new bride worships the tap in her home. Can we even imagine life

without water? Devraj

Think over it:

In 1986, there was no rain in Jodhpur and the surrounding areas. People remembered the old and forgotten stepwell (baoli). They cleaned the stepwell and more than two hundred trucks of garbage was taken out of it. People of the area collected money.

The thirsty town got water from the stepwell. After a few years it rained well and again the stepwell was forgotten.

There are two old wells in the area where Punita lives. Her grandmother says that about fifteen - twenty years ago there was water in these wells. The wells could have dried up because:

Water is being pumped up from under the ground, with the help of electric motors.

The lakes in which rain water used to collect are no longer there. The soil around trees and parks is now covered with cement.

This is how we get water:

A Jal Board water tanker comes to our colony twice a day. We have to stand in a long queue to get water from the tanker. People at times We fill water from the well.

The nearby well dried up a year ago. Now we have to walk far to reach the other well.

We are not allowed to take water from some of the wells because of our caste. have fights over water. We get water at home for half an hour. We fill this in the tank to use all day. Sometime it is dirty.

We get water from our taps, all day long.

We have put a pump directly in the Jal Board pipeline. Now we don't have any problem! We have put a motor to pump up the water from the borewell. But there is no electricity, so what do we do!

There is a handpump nearby, but the water that we get from it is salty. We have to buy water for drinking.

We get water from the canal itself.

It can be done:

There are some groups that work hard to bring water to the people of different areas. They ask the elders about the water arrangement in their times.

They rebuild the old lakes and johads, and also build new ones. Let us see how the group called Tarun Bharat Sangh helped Darki Mai. This is Darki Mai. She lives in a village in the Alwar district of

Rajasthan.

The women of the village used to spend the entire day looking after their home and animals. Sometimes, it took them all night to pull water from the well for the animals. In the summer, when the wells dried up, they had to leave the village.

Darki Mai heard about this group and asked for help. Together, the people from the group and the village decided to make a lake. The problem of food and water for animals is now less. People get more milk. They have started earning more.

THANKYOU,

NANDITHA AKUNURI